Okay, so imagine you're playing a game with your friends, and one of your friends keeps trying to cheat and mess up the game so they can win. That's kind of what happened with the 2020 elections. The United States was having a big election to choose who would be the next president, and some people from Russia tried to cheat and mess up the election so that the person they wanted to win would win instead.
They did this in a few different ways. One way was by trying to spread fake news and lies about the candidates, to make people think one candidate was really bad and the other was really good. They also tried to hack into the computer systems that help run the election, to try to change the votes or mess up the results.
This is very bad because it means that the election might not be fair and the person who actually won might not get to be the president. It's like playing a game where someone keeps cheating - it's not fun and it's not fair. People are working really hard to make sure this doesn't happen again in future elections.